Pseudofolliculitis barbae (/ˈsjuːdoʊfəˈlɪkjʊˈlaɪtɨsˈbɑrbiː/; PFB), also known as barber's itch, folliculitis barbae traumatica, razor bumps, scarring pseudofolliculitis of the beard, and shave bumps, is a medical term for persistent irritation caused by shaving.[1][2] Pseudofolliculitis barbae was first described in 1956.[3]

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Pseudofolliculitis barbae (PFB) is most common on the male face, but it can also happen on other parts of the body where hair is shaved or plucked, especially areas where hair is curly and the skin is sensitive, such as genital shaving (more properly termed pseudofolliculitis pubis or PFP).

After a hair has been shaved, it begins to grow back. Curly hair tends to curl into the skin instead of straight out the follicle, leading to an inflammation reaction. PFB can make the skin look itchy and red, and in some cases, it can even look like pimples. These inflamed papules or pustules can form especially if the area becomes infected.

This is especially problematic for some men who have naturally coarse or tightly curling thick hair. Curly hair increases the likelihood of PFB by a factor of 50.[4] If left untreated over time, this can cause keloid scarring in the beard area.

Pseudofolliculitis barbae can further be divided into two types of ingrown hairs: transfollicular and extrafollicular. The extrafollicular hair is a hair that has exited the follicle and reentered the skin. The transfollicular hair never exits the follicle, but because of its naturally curly nature curls back into the follicle causing fluid build-up and irritation.

A common polymorphism in a keratin gene (K6hf) has been linked to PFB, suggesting that it may be a geneticrisk factor.[5] This sequence change leads to an amino acid substitution in the highly conservedhelix initiation motif of the K6hf rod domain.[4] Carriers of the A12T polymorphism are six times more likely to develop PFB compared with people homozygous for the wild-type K6hf sequence.[5] This suggests K6hf mutation structurally weakens the companion layer separating the inner and outer root sheath and increases the chances that a beard hair will in-grow.[5]

The most effective prevention is to let the beard grow.[6] For men who are required or prefer to shave, studies show the optimal length to be about 0.5 mm to 1 mm to prevent their hair growing back into the skin.[6] For most cases, totally avoiding shaving for three to four weeks allows all lesions to subside, and most extrafollicular hairs will resolve themselves in about 10 days.[6] Permanent removal of the hair follicle is the only definitive treatment for PFB.[6]Electrolysis is impractical and ineffective because the needle may not reach the hair follicle.[6]Laser-assisted hair removal is effective.[6] There is a risk of skin discoloration and a very small risk of scarring.

Some men use electric razors to control PFB. Those who use a razor, should use a single blade or special wire-wrapped blade to avoid shaving too closely, with a new blade each shave.[6] Shaving in the direction of hair growth every other day, rather than daily, may improve pseudofolliculitis barbae. If one must use a blade, softening the beard first with a hot, wet washcloth for five minutes or shave while showering in hot water can be helpful. Some use shaving powders (a kind of chemical depilatory) to avoid the irritation of using a blade. Barium sulfide-based depilatories are most effective, but produce an unpleasant smell.[6]

The easiest cure is to let the beard grow.[6] Existing razor bumps can often be treated by removal of the ingrown hair. Extrafollicular hairs can usually be pulled gently from under the skin, with tweezers. Complete removal of the hair from its follicle is not recommended. Severe or transfollicular hairs may require removal by a dermatologist.

Medications are also prescribed to speed healing of the skin. Clinical trials have shown glycolic acid-based peels to be an effective and well-tolerated therapy which resulted in significantly fewer PFB lesions on the face and neck.[6] The mechanism of action of glycolic acid is unknown, but it is hypothesized that straighter hair growth is caused by the reduction of sulfhydrylbonds in the hair shaft by glycolic acid, which results in reduced re-entry of the hair shaft into the follicular wall or epidermis.[6] Medications containing Allantoin and Azulene have been shown to reduce swelling, redness and itchiness. Allantoin is a natural soothing skin protectant and moisturizer that increases the water content to provide structure support to skin cells. Azulene is a blue colored oil derived from flowers in the Asteraceae family and can be used to moisturize and soothe irritated skin.[7]Salicylic acid peels are also effective.[8] Prescription antibiotic gels (Benzamycin, Cleocin-T) or oral antibiotics are also used. Retin-A is a potent treatment that helps even out any scarring after a few months. It is added as a nightly application of Retin-A Cream 0.05 - 0.1% to the beard skin while beard is growing out.

Exfoliating the skin before and between shaves using an ingrown hair brush or bump brush effectively frees trapped hair out and teases it away from the skin before the hair has a chance to embed itself. [9]

Razor burn is a less serious condition caused by shaving, characterized by mild to moderate redness and irritation on the surface of the skin. Unlike PFB, it is usually transient and there is no infection involved.

There is also a condition called folliculitis barbae. The difference between the two is the cause of the inflammation in the hair follicles. Folliculitis barbae is caused by viral or bacterial infections, where pseudofolliculitis is caused by irritation from shaving and ingrown hairs.

A related condition, pseudofolliculitis nuchae, occurs on the back of the neck, often along the posterior hairline, when curved hairs are cut short and allowed to grow back into the skin. Left untreated, this can develop into acne keloidalis nuchae, a condition where hard, dark keloid-like bumps form on the neck.